Every so often, I'm invited to speak to students about my work and someone asks what's the hardest part of my job. I'm not sure what answer they expect, but they always seem surprised when I say that it can be physically difficult.

Except for a bout with repetitive stress injury a few years back (brought on by bicycling in San Francisco), it's not the writing, but the reading that gets to me. A lot of sitting is never good for your body (I get a surprising amount of reading done on...